Rheumatology · Medical Literature
The short-term efficacy of heat therapy for osteoarthritis of the hands: a systematic review and meta-analysis.
Abstract
To systematically evaluate the clinical efficacy of heat therapy for hand osteoarthritis. Systematic review and meta-analysis of randomized controlled trials (RCTs). 9 RCTs (n = 627) from 13 identified studies included in meta-analysis. Databases were searched up to 19 December 2025. Risk of bias was assessed via RoB 2.0. Standardized mean differences (SMD) and meta-regression were calculated using Stata 17.0. Heat therapy significantly reduced Visual Analog Scale (SMD = -0.60, p = 0.01), Australian/Canadian Osteoarthritis Hand Index - Pain Score and Health Assessment Questionnaire (p < 0.05), and improved grip strength (SMD = 0.43, p = 0.01). No significant changes were observed for other outcome indicators. Subgroup analysis showed multimodal therapy (paraffin: heat + mechanical compression; mud: heat + chemical/mechanical stimulation) outperformed monotherapy (-heated gloves: pure thermal) for pain (SMD = -0.85) and grip strength (SMD = 0.55). Additionally, meta--regression analysis found that longer single -treatment duration (p = 0.03) and higher weekly t-reatment frequency (p = 0.04) were key moderators for better grip strength recovery. Heat therapy, especially multimodal approaches, effectively alleviates short-term pain and improves grip strength in hand osteoarthritis. Clinicians may ensure adequate treatment frequency and duration to optimize outcomes.
Clinical relevance
In adults with hand osteoarthritis, does heat therapy—compared with control conditions—significantly reduce pain and improve grip strength and functional outcomes over short-term follow-up? __SNAPSHOT__ {"studyDesign":"Systematic review and meta-analysis of randomized controlled trials (RCTs); risk of bias assessed using RoB 2.0; statistical analysis via Stata 17.0 using standardized mean differences (SMD) and meta-regression","setting":"Multi-database literature search (databases searched up to 19 December 2025); specific databases not reported in abstract","sampleSize":"n = 627 across 9 RCTs (from 13 identified studies); individual trial sample sizes not reported in abstract","population":"Adults with hand osteoarthritis; further demographic details (age, sex distribution, OA severity, disease duration) not reported in abstract","intervention":"Heat therapy modalities including: (1) multimodal therapy — paraffin bath (heat + mechanical compression) and mud therapy (heat + chemical/mechanical stimulation); (2) monotherapy — heated gloves (pure thermal application)","comparator":"Control conditions not explicitly described in abstract; assumed to include no treatment, sham, or active comparator arms as reported in constituent RCTs","primaryOutcome":"Not formally designated as a single primary outcome in the abstract; outcomes assessed included pain (Visual Analog Scale [VAS], Australian/Canadian Osteoarthritis Hand Index [AUSCAN] Pain Score, Health Assessment Questionnaire [HAQ]), grip strength, and other unspecified indicators","followUp":"Described as 'short-term'; specific duration not reported in abstract","fundingSource":"Not reported"}
Key findings
Across 9 RCTs (n = 627), heat therapy was associated with a statistically significant reduction in pain on the Visual Analog Scale (SMD = −0.60, p = 0.01), which by Cohen's conventions represents a moderate effect size. Pain improvements were also statistically significant on the AUSCAN Pain Score and HAQ (p < 0.05 for both; SMD values not reported in abstract). Grip strength improved significantly (SMD = 0.43, p = 0.01), representing a small-to-moderate effect size. No significant changes were observed for other outcome indicators (not specified in abstract). Subgroup analysis favored multimodal heat therapy (paraffin: heat + mechanical compression; mud: heat + chemical/mechanical stimulation) over monotherapy with heated gloves (pure thermal) for both pain (SMD = −0.85 vs. comparator SMD not reported) and grip strength (SMD = 0.55 vs. comparator SMD not reported), suggesting additive benefit from mechanical or chemical co-stimulation. Meta-regression identified longer single-treatment session duration (p = 0.03) and higher weekly treatment frequency (p-value and frequency thresholds not fully reported in abstract—abstract appears truncated) as moderators associated with greater benefit. No absolute risk differences, NNT, or NNH are calculable from the reported data. No adverse events were described in the abstract.
Practice implications
This meta-analysis provides pooled evidence that short-term heat therapy produces statistically significant, moderate-magnitude reductions in hand OA pain and modest improvements in grip strength. The finding that multimodal therapies (paraffin bath, mud therapy) outperform pure thermal application (heated gloves) is clinically plausible given the additional mechanical compression component of paraffin and mud baths, which may independently reduce swelling and improve joint mobility. However, several important limitations preclude firm clinical conclusions: (1) only the abstract was available for review, preventing assessment of heterogeneity statistics (I² values), individual study characteristics, blinding adequacy, or control arm descriptions; (2) the meta-regression finding regarding session duration and weekly frequency is incompletely reported (abstract appears truncated), limiting dose-response interpretation; (3) 'short-term' follow-up is undefined, meaning durability of benefit is entirely unknown; (4) patient-level demographic and disease-severity data are not reported, limiting generalizability to specific hand OA subpopulations (e.g., erosive vs. non-erosive OA, interphalangeal-predominant vs. thumb CMC-predominant disease); (5) SMDs of 0.43–0.60 are statistically significant but may not universally cross minimal clinically important difference (MCID) thresholds; and (6) the abstract describes no adverse event data, so safety cannot be commented upon. These findings are supportive of heat therapy as a component of multimodal non-pharmacological management of hand OA, consistent with current ACR guideline conditional recommendations for thermotherapy, but should not be interpreted as establishing heat therapy as superior to other physical modalities or as a replacement for exercise or pharmacologic therapy. __LIMITATIONS__ Only the abstract was available; full-text review was not possible, precluding assessment of heterogeneity (I² not reported), pooling methodology validity, and control arm definitions.,Short-term follow-up duration is not quantified; long-term durability of benefit is entirely unknown and cannot be inferred.,The abstract appears truncated, leaving meta-regression findings for weekly treatment frequency incompletely reported.,Small total sample (n = 627 across 9 RCTs) limits statistical power for subgroup and meta-regression analyses and increases risk of spurious findings.,Individual RCT blinding status is not described; blinding of participants to heat therapy is inherently difficult (performance bias likely).,Control arm heterogeneity across constituent RCTs (no treatment, sham, active comparator) may introduce clinical heterogeneity not adequately addressed.,Patient-level characteristics (age, sex, OA severity, comorbidities) are not reported, limiting generalizability.,Outcome heterogeneity across RCTs (VAS, AUSCAN, HAQ used across different studies) may affect validity of pooling despite use of SMD.,Funding source is not reported; potential for publication bias in thermotherapy trials (positive results more likely to be published) is not discussed in the abstract.,Adverse event data are not reported, leaving safety profile undefined. __BOTTOM_LINE_CATEGORY__ potentially_practice_informing __BOTTOM_LINE__ This systematic review and meta-analysis of 9 RCTs (n = 627) found that short-term heat therapy produced statistically significant, moderate reductions in hand OA pain (VAS SMD = −0.60) and small-to-moderate improvements in grip strength (SMD = 0.43), with multimodal therapies (paraffin bath, mud therapy) outperforming pure thermal application. Given the small pooled sample, undefined follow-up duration, truncated meta-regression reporting, and abstract-only availability, these results are supportive of—but insufficient to substantially change—current practice; heat therapy, particularly paraffin bath, remains a reasonable adjunct non-pharmacological option in hand OA management consistent with existing conditional guideline recommendations, pending confirmation from larger, adequately powered RCTs with standardized protocols.